Evidence overwhelmingly suggests that the built environment has an impact on people’s health, particularly in terms of noncommunicable diseases such as asthma, diabetes and poor mental health. However, health is rarely prioritised in urban planning decisions at present, and earlier work by this research group has shown that senior decision-makers feel they lack the power to influence planning and policy decisions in order to improve the situation. This intervention area adds to the wider research programme, which is focused primarily on the delivery of quantifiable socio-environmental and health economics valuations. People make decisions not just based on economic valuation, so an understanding of why people make decisions and how those decisions can change is essential. This paper describes the methodology that will be used to develop this intervention. Findings will be published later.